1. Field of the Invention
This invention relates to a calculator device which allows a bowler to predict spots on each of two bowling lanes by reference to an adjustable ball characteristic line as defined by two interchangeable covers. As is well-known, 10-pin bowling alleys include lane markers or "spots" positioned at various points along the elongated length of the alley. It is common for a bowler to select particular lane spots as an aiming device, so that the habitual curvature of that bowler, on that alley, will result in a final contact between a bowling ball and the bowling pins that is most effective for the situation. Each alley has characteristics peculiar to itself, and it is common for a bowler to adjust his orientation behind a foul line to most effectively match his characteristic ball curvature on that alley to the indicia upon the bowling lane.
The present invention is particularly directed to bowling as is done under tournament conditions, wherein a bowler necessarily transfers from a first lane to a second lane, and must develop a characteristic ball travel line for each of two lanes. The present invention, therefore, allows for the quick interposition of two superposed covers onto a frame carrying bowling lane indicia during a bowling exercised conducted on two lanes